How can we optimize and better understand the interactions within an aquaponic system to improve nutrient cycling, water quality, and overall productivity? Aquaponics is a method of raising fish and growing plants for food within a single, recirculating system. Rooted in practices dating back to the Aztecs, aquaponics has gained renewed interest among commercial growers, organic gardeners, and sustainability advocates because of its potential as a low-cost, efficient method of producing vegetables and high-protein food in limited space and diverse environments. In this term-long, project-based elective, students will use an aquaponic system engineered by previous students as a living laboratory to investigate ecological systems, nutrient cycling, and sustainable food production. Beyond construction, students will design and conduct experiments to better understand how biological, chemical, and physical factors influence system health and productivity. Students will explore topics such as nitrogen cycling, microbial communities, plant nutrient uptake, fish health, water chemistry, and system efficiency. They will develop testable hypotheses, collect and analyze data, modify variables, and evaluate the impact of their experimental designs. Projects may include testing different growing media, adjusting feeding rates, comparing plant species, monitoring ammonia/nitrite/nitrate dynamics, or exploring methods to improve filtration and nutrient balance. The course emphasizes systems thinking, experimental design, data analysis, and iterative problem-solving. Students will collaborate to identify constraints, analyze system performance, and propose evidence-based improvements. This class is taught using a “one-room schoolhouse model,” where students with varying levels of experience work together on shared investigations. Assignments are differentiated to match each student’s background and experience, allowing students to take the course for multiple terms while deepening their scientific understanding and research skills.